Carburetor



March 31, 1936. ER 7 2,035,636

CARBURETOR Filed April 1, 1935 WILTON E Kym/ 45 INVENTOR ATTORNEY Patented Mar. 31, 1936 6 Claim.

This invention relates to improvements in the accelerating means for plain tube carburetors.

The problem to be solved is briefly:-

(a) To provide an accelerating fuel pump which discharges into the main mixingchamber and supplements the main fuel nozzle.

(b) To provide means which will temporarily enrich the gasoline flowing through the mainnozzle during theper'iod after the throttle has been opened when the engine depression in the mixture outlet of the carburetor is low and to restore the economical fuel mixture ratio after the air flow has increased to the point where the depression in the mixture outlet has been restored. Figure 1 shows the layout of the carburetor diagrammatically.

Figure 2 shows the mechanical details of the accelerating pump.

Figure 3 shows the plan view looking down on plane 3-3 of Figure2.

Figure 4 shows an alternative construction for the pump shown in Figure 2.

Figure 5 shows thermeans temporarily enrichening the fuel mixture ratio.

. Figure 6 shows an alternative method for en? richening the mixture.

. In the flgures, i0 is the air entrance, II is the fuel passage extending tranversely through 'the air entrance. The passage II is provided with a fuel restriction i3 and an air vent l2,

both of which are located above the level l4-l4 which is maintained by a float in a float chamber 23. This float chamber is vented to the atmosphere through an opening 21 and is pro- 35 vided with a fuel connection 23. The constant level fuel supply chamber 23 is provided with a iueloutlet 82 which supplies fuel throu h a restriction 3| to an air vented fuel well 22 which is vented to the atmosphere at I. and is pro-- vided with a perforated tube 2|. the upper perforation of which, I3, is located just below the level l4-|4. The air vent l3 leadsinto the outer portion of the well 20 so that when fuel is drawn through II and the level drops in 20, by reason 45 of the restriction 3!, air can flow from l8 through l9 to the passage ll. v

A main fuel nozzle 40 is connected to Ii and discharges into the throat of a venturi 4|. This venturi 4| forms a mixing chamber which leads to a mixture outlet 45 controlled by a butterfly throttle 48. A low speed fuel passage 42 forms the continuation of the transverse fuel' passage I l which thus discharges into 45 through the two low speed outlets 43-44; 44 being located on the 55 engine side, 43 being located on the atmospheric diagrammatically in Figure 1. passage 48 connects the mixture outlet 45 through side of the butterfly throttle' 46 when 46 is in the closed position. The fuel'outlet 44 is controlled by the needle valve 49. This low speed construction is the orthodox low speed construction now in general use. 5

'A throttle lever 36 is connected to a link 35 to a rod l5 which is bent over 180" and connected through a compression spring Hi to an accelerating fuel piston I! so that when the throttle 46 is opened suddenly the piston I1 is pushed down 10 by reason of the compression of the spring I8. I Fuel is supplied to-a cylinder 34 in which the piston il reciprocates past a check valve 33. Fuel is discharged from 34 through apassage 31 past a check valve 38 and discharges through an orifice 5 39 located substantially at the level I4-i4 and above the point of discharge of the main fuel nozzle 40 which is located definitely below the level l4l4 and in the throat of the venturi M.

A packing ring 5|, shown in greater detail in 20 Figure 2, is provided in the cylinder 34 to prevent the leakage of fuel past the piston IT.

The means for enrichening the mixture through the main fuel nozzle 40 when the depression in the mixture outlet 45 is temporarily de- 25 stroyed by'the sudden opening of the throttle 46, during theperiod when the engine picks up speed and thereby restores the depression in '45 as is shown in detail in Figures 5 and 6 and also In Figure l a a restriction 41 with a chamber 26. This chamber 26 is provided, with a flexible diaphragm numbered 25 in Figure 1 and M- in Figure 5. Thisflexible diaphragm controls a shut-oi! valve 23. This shut-oil valve 23 controls the flow of fuelthrough ah-passagetfl andgis unseated by a spring 59. The depression in 45 thus serves to close the flow of fuel-through 24. The passage 24 is connected through a restriction 30; with a main fuel passage 32. A passage '22 admits the 7 fuel from 30 to the air vented well 20 and thereby enriches the mixture during the time that the depression in falls below a. certain figure determined by the stiffness of the spring 53 and 45 the area of the flexible diaphragm.

In Figure 6 an alternative form of construction is shown in which a fuel passage 60 is shown in free communication with the passage 32 and a restriction-'58 is provided in place of the free communication 32. By this means full atmospheric pressure is applied to the flexible dia- I phragm 25.

municating with ,a chamber I} which corresponds to 2| in Figure 1. The vacuum admitted through ing chamber therein, and a fuel nozzle discharg- 48 is eil'ective against the diaphragm," which is clamped by a washer '54 to the shut-oil. valve \23. The diaphragm is mounted in a cage 6| which is threaded into a casting 62." 6| carries an opening 24 which opening is controlled by the shut-oif valve 23 controlled by the spring 59. Fuel flows through the opening 22. into the air vented well 2 0. Fuel is supplied to the passage 32 from the float chamber 29 (not shown) through the restricted oriflce I3 and so through the .opening 24 controlled by the shu -oif valve 23. The piece 6| is provided with an opening 61 so that fuel flows from 53 through 83 through the opening 24 and so through 22 to the air vented well 24 In order to make the vacuum admitted through 48 effective against the diaphragm 8| a stamped cup 52 encloses the space 55 in which is located the cage 6| which carries the diaphragm I]. The diaphragm II can thus be removed and the compression spring 59 adjusted.

- In Figures 2,3 and 4 the details of,the accelerating fuel pump are shown in detail. The rod ill is provided with a spring Ii and is adap to slide through the plate 51, which plate is ripped to the cylinder II. The piston I1 is,

shown sliding in a cylinder 34 which is located on the side of the float chamber 29 so that any fuel which escapes past the packing II is caught in the float chamber a. This packing 5| is one of the novel features of my invention. It consists of a flexible leather packing in the wall of the cylinder 34 which cheapens the cost of making the piston l-I. ii is retained in acage 64 and is pported by a packing ring-CI.

In Figure 4 the rod "is shown sliding in a piece it which'is provided with a re-entering angle on its surface so'that the tube-[1 can be spun over andlocked to 54.

By providing a restriction 41 between the mixture outlet 45 and the diaphragm chamber 55 (Figure 5.) or 24 (Figures 1 and 6) I delay the I action of the shut-oil valve "and thereby pro shut ofl valve in said e connected to said flexible wall, a fuel entrance leading to'said cage, .aremovable cap. adapted to cover the flexible wail of said cage, a suction passa e adapted to a connect the mixture outlet with the space between said cap and said flexible wail, said cap being long the period. of rich mixture so that the mixture does not immediately become lean after the throttle is closed nor does the mixture immediately become rich-after the throttle is opened. The advantage of this is that the mixture only becomes-rich after the accelerating pump has ceased to functior and then only in the event that the engine does not accelerate to the point that the depression in the mixtm-e is sumcient to hold the shut-oif-valve closed;

,What I claim is:

1. An enrichening device for a carburetor having a mixture outlet, a mixing chamber'and a fuel nozzle discharging therein, comprising a cage mounted on said carburetor, a flexible outer wail therefor, a fuel outletpassage to said cage, a

adapted to be removed without disturbing said suction passage.

" 2. A device as set forth in claim 1 having a restriction in said suction passage for :19 purpose described. a

and enclosing said flexible *mitting mixture outlet suction to the inside of 3. An enrichening device for a carburetor having a main body casting, a mixture outlet, a mixing into said mixing chamber comprising a hollow unitary structure adapted to be threaded at one end into said carburetor body and having on its other end a flexible wall, a fuel entrance leading into said hollow structure and a fuel outlet leading therefrom, a shut-off valve controlling the flow from said inlet to said outlet, said valve being operatively connected to said flexible wall, means for applying mixture outlet suction to said flexible wall consisting of a cap, a suction passage leading to the inside of said cap, said cap being adapted to be removed without disturbing said suction passage.

4. An enrichening device for a carburetor having a main body casting, a mixture outlet, a mix-- ing chamber therein-and a fuel nozzle discharging into said mixing chamber, comprising a hol- 2 ably mounted in said carburetor casting, said valve being connected to said flexible wall, said valve extending beyond said structure, a spring mounted on said extension adapted to open said valve, means 'for adjusting said spring, a removable cap mounted on said carburetor casting wall, means for adsaid cap, said cap being adapted to be removed without disturbing means.

5.,An enrichening device for a carburetor having a main body casting, a mixture outlet, a

mixing chamber therein and a fuel nozzle discharging into said mixing chamber, comprising a hollow bell shaped structure removably mount,- ed in said casting and having a fuel entrance into its side and a fuel outlet in its smaller end 40 in communication with said'mixing, chamber, a shut-oi! valve located on the outside of said end, l diaphragm mounted on the larger end and connected to said valve, a removable cap enclosing said diaphragm, a passagein' said casting con-' necting the inside of said cap with said mixture outlet, said cap being adapted to be removed without disturbing said passage.

- 6. An enrichening device for a carburetor hav- I ing a main bodycasting, a mixture outlet, a

mixing chamber tlierein and a fuel nozzle discharging into said mixing chamber, comprising an opening in the side of said carburetor casting, a fuel passage in said casting discharging into said opening, a hollow bell shaped structure'having its two ends open mounted in said opening to control the flow through said fuel passage, an opening through the side of said structure, a shut-oil valve located in the smaller open end of said structure, a diaphragm adapted to close the larger opening of said structure, said diaphragm being connected with said valve, a'suction passage through said carburetor casting leading from I said mixture outlet and terminating near said diaphragm, a removable cap adapted to enclose both said diaphragm and said suction passage outlet, said cap being adapted to be removed without m 'b fi De. 1 1, 

